Re: Change the default maximum TTree size

Hi Vladimir,

in hadd the maximum limit is set to 100 GBytes

Rene Brun

Vladimir Savinov wrote:
> Dear Rene,
> when one needs to merge a large number of TTrees using hadd,
> is there a hardwired limit on this length, or hadd would be able to
> choose the correct maximum tree size automatically?
> thanks,
> Vladimir
>
>
>
> Rene Brun wrote:
>> No, we will not change the MaxTreeSize for several reasons.
>> It is trivial to change it yourself with a statement like
>> //Authorize Trees up to 2 Terabytes (if the system can do it)
>> TTree::SetMaxTreeSize(1000*Long64_t(2000000000));
>>
>> Rene Brun
>>
>> Ida Häggström wrote:
>>> Hello!
>>>
>>> I'm a new ROOT-user (version 5.24) and have a question regarding the
>>> maximum TTree file size. I'm running a Monte Carlo simulation
>>> software called Gate (based on Geant4) which produces ROOT output.
>>> I've understood the maximum allowed file size by default is 1.9GB,
>>> but could be changed to something larger if your OS allows it. I run
>>> CentOS 5 Linux with file system ext3 and I think the maximum size
>>> should be at least 16GB. I've briefed through the forum and users
>>> guide and found that you can change the maximum allowed size via the
>>> command TTree::SetMaxTreeSize(). This only applies for that
>>> particular instance of ROOT however (right?), when you exit and
>>> start a new ROOT you have your default settings again. Using Gate, I
>>> never open ROOT myself during the creation of the output files... I
>>> wonder if you can change the default 1.9GB to say 16GB instead? In
>>> the TTree.h file, line 393
>>>
>>> static void SetMaxTreeSize(Long64_t maxsize = 1900000000);
>>>
>>> Can you change the size here and recompile Root to get the new
>>> default?? Thank you!
>>> Ida
Received on Tue Nov 03 2009 - 17:31:45 CET